Design of LED setup for measuring tandem solar cell subcell J-V behaviour

The need to accurately measure multi-junction (MJ) tandem solar cells' subcell current-voltage characteristics is increasing due to the vital information they provide about the efficiency, stability, and longevity of the cells. These measurements are rather difficult compared to their counterpart single-layer solar cell measurements. The purpose of this project is to construct an instrument that is able to successfully bias multiple subcells in a tandem solar cell. This would allow accurate measurements of the J-V behaviours of individual subcells within the stack and by extent, allow analysis to optimise future tandem cell technology. The instrument made is a controllable multi-chromatic light-emitting diode array, consisting of six wavelength-different LEDs ranging between ultraviolet and infrared light, which the intensity of is controlled bya slider control Graphical User Interface (GUI). This instrument will bemounted on a laboratory station at the institution of solar cell technology, Ångström laboratory. Although not perfect, the instrumentcan provide sufficient background light for biasing subcells of an MJ solar cell for a wide selection of cell band gaps